A characteristic of automotive vehicles particularly of the station wagon type is that, in use, air turbulence causes a low pressure air pocket to form behind the vehicle body that drags against forward motion of the vehicle and adversely affects fuel economy. Also, the low pressure air pocket causes road splash and dust to swirl in behind the vehicle and coat the rear end including the rear window and the tail and signal lights. This layer of road splash, dust and grime frequently accumulates in sufficient amount to impair visibility of the lights and to obstruct the view through the rear window which creates a driving hazard.